Appendix 4, Page 1 Marine Invertebrates – Introduction Marine ecosystems worldwide are being altered by human disturbances such as overfishing (Botsford et al. 1997; Jackson et al. 2001; Pauly et al, 2002; Myers and Worm 2003) coastal shoreline development, climate change, and eutrophication (Howarth et al. 2000; Rabalais et al. 2002), and these impacts are beginning to be felt in Alaska. Achieving sustainability of resources, economies, coastal communities and the ecosystems in which these are all embedded requires conservation strategies that acknowledge the complex social and ecological interactions that drive marine ecosystem dynamics (Scheffer et al. 2001; Walker et al. 2002). The focus of this template is on the approach that will be used for conservation planning, one that encompasses the ecological relationships among multiple species and habitats. Literature Cited Botsford, L.W., Castilla, J.C., and C.H. Peterson. 1997. The management of fisheries and marine ecosystems. Science 277: 509–515. Howarth, R.W., D. Anderson, J. Cloern, C. Elfring, et al. 2000. Nutrient pollution of coastal rivers, bays, and seas. Issues in Ecology. 7:1–5. Jackson, J.B.C., M.X. Kirby, W.H. Berger, K.A. Bjorndal, L.W. Botsford, B.J. Bourque, R.H. Bradbury, R. Cooke, J. Erlandson, J.A. Estes, T.P. Hughes, S. Kidwell, C.B. Lange, H.S. Lenihan, J.M. Pandolfi, C.H. Peterson, R.S. Steneck, M.J. Tegner, and R.R. Warner. 2001. Historical overfishing and the recent collapse of coastal ecosystems. Science 293:629–638. Myers, R.A. and B. Worm. 2003. Rapid worldwide depletion of predatory fish communities. Nature 4:280–283. Pauly, D., V. Christensen, S. Guénette, T.J. Pitcher, U.R. Sumaila, C.J. Walters, R. Watson, and D. Zeller. 2002. Towards sustainability in world fisheries. Nature 418:689–695. Rabalais, N.N., R.E. Turner, and W.J. Wiseman, Jr. 2002. Hypoxia in the Gulf of Mexico, a.k.a. “The Dead Zone.” Annual Review of ecology and Systematics 33: 235–263. Scheffer, M., S. Carpenter, J.A. Foley, C. Folke, and B. Walker. 2001. Catastrophic shifts in ecosystems. Nature 413:591–596. Walker, B., S. Carpenter, J. Anderies, N. Abel, G. Cumming, M. Janssen, L. Lebel, J. Norberg, G.D. Peterson, and R. Pritchard. 2002. Resilience management in social-ecological systems: a working hypothesis for a participatory approach. Conservation Ecology 6(1):article 14. Appendix 4, Page 2 Nearshore Soft Benthic Ecosystems This ecosystem extends from the intertidal to the shallow subtidal (+ 6 m to –30 m) and includes eelgrass, mud, sand and gravel habitats. We identified 2 species assemblages of concern: 1) intertidal and shallow subtidal bivalves and 2) eelgrass-associated invertebrates. An ecosystem-based approach to the conservation of these assemblages would acknowledge the complex food web interactions between structure forming plants (e.g., Zostera marina), stabilizing algae (e.g., Enteromorpha, Cladophora, diatom films), nongame bivalves (e.g., Macoma spp., Serripes spp., Clinocardium spp., Mactromeris spp. Tellina spp., Nucula spp. and Yoldia spp.), harvested bivalves (e.g., Protothaca staminea, Saxidomus giganteus, Panopea abrupta), sediment bioturbators such as infaunal polychaetes and epifaunal gastropods, generalist predators (e.g., dungeness crabs and sunflower stars), bottomfish that inhabit this “nursery” ecosystem (e.g., sand lance, sand sole, starry founder, juvenile salmonids), shorebirds (e.g., sandpipers, ducks and geese) that depend on secondary consumers (shrimp, worms, small bivalves) as a primary source of food, and finally, marine mammals (e.g., harbor seals, sea otters and gray whales) that also forage in this ecosystem. Some ecosystem dynamics to consider: • Freshwater and nutrient inputs from upstream watersheds influencing nearshore water and sediment chemistry (i.e., hypoxia) and sediment grain size • Oceanic nutrient inputs from offshore upwelling and marine derived nutrients from returning salmonid species • Water filtration rates • Sedimentation vs. erosion rates • Bacterial activity and detrital cycling • Benthic pelagic coupling and microbial decomposition • Biofilms (diatoms) stabilizing nearshore sediments Eelgrass Invertebrates A. Species group description Common name: eelgrass-associated invertebrates Scientific names: a variety of invertebrates associate with eelgrass Zostera marina including: eelgrass shrimp Hippolyte clarki, hydroids Obelia spp., snails Lacuna spp., caprellid amphipods, Dungeness crab Cancer magister, helmet crab Telmessus cheiragonus, kelp crabs Pugettia spp., horse clams Tresus capax, sea cucumbers Parastichopus californicus, spionid polychaetes, nudibranches including Melibe leonina (Kozloff 1993; Ricketts et al. 1985) Selection criteria: Eelgrass beds are among the most productive ecosystems on the planet. The invertebrates associated with eelgrass play a key role in transferring energy from the eelgrass to higher trophic levels (Nelson and Waaland 1997; Johnson et al. 2003). Appendix 4, Page 3 B. Distribution and abundance Range: (McRoy 1966; McRoy and Helfferich 1977) Global range comments: Zostera marina is discontinuous from the Sea of Okhotsk and Japan, the Baltic Sea, the Mediterranean Sea, the North Pacific as far south as Agiopampo Lagoon, Mexico State range comments: North to Port Clarence, west to Atka Island, the Gulf of Alaska including the Southeast Panhandle Abundance: Global abundance comments: Unknown State abundance comments: Unknown Trends: Global trends: Generally declining State trends: Unknown C. Problems, issues, or concerns for species group • Eelgrass invertebrates act as a crucial link in transferring energy from eelgrass production to higher trophic levels (Shirley 2003) • The distribution of eelgrass across the state is poorly known and the associated invertebrate assemblages are also poorly documented • Eelgrass is vulnerable to destruction from turbid water and fishing gear • Pesticides used in mariculture can directly affect eelgrass-associated invertebrates (Thayer et al. 1975; Griffin 1997) • Many of the associated invertebrates are dependent upon the eelgrass environment and are severely impacted by the disappearance of eelgrass beds (Stauffer 1937). • Disease (Rasmussen 1977; Levinton 1982) D. Location and condition of key or important habitat areas Unknown. An evaluation of location and condition of this habitat is needed. E. Concerns associated with key habitats • Light availability is an important factor limiting eelgrass growth; the amount of light reaching eelgrass can be influenced by human activities, such as sediment loads caused by logging and streamside activities. • Eutrophication is regarded as a major factor of eelgrass bed declines because it stimulates the overgrowth of epiphytic algae (Huges et al. 2004). • High nutrient input from fertilizers, sewage, and fish waste can result in excessive epiphyte growth on eelgrass blades that can also deprive eelgrass of light. • Pesticides used to control invertebrates in mariculture operations may also kill the invertebrates in nearby eelgrass beds (Thayer et al. 1975; Griffin 1997). • Coastal development has been the primary cause of widespread seagrass loss (Short and Wyllie-Echeverria 1996). Appendix 4, Page 4 • Physical disturbance via commercial fishing gear (Stephan et al. 2000; National Research Council 2002; Trush and Dayton 2002) has been identified as a significant source of seagrass habitat destruction. Trawling, dredging and raking for bay scallops (Fonseca et al. 1984), mussels (Neckles et al. 2005), and hard clams (Peterson et al. 1983) have been found to damage eelgrass beds (Johnson 2002). • Other activities such as dredging (Thayer et al. 1984), and associated construction of boat docks and harbors (Burdick and Short 1999) significantly impact eelgrass habitats. • On-bottom shellfish aquaculture in close proximity to eelgrass beds can lead to habitat destruction as farmers access their beds. Geoduck mariculture may also affect eelgrass beds. F. Goal: Conserve and manage eelgrass-associated invertebrate populations throughout their natural range to ensure sustainable use of these resources. G. Conservation objectives and actions Objective: Sustain species diversity, population density and size structure of eelgrass- associated invertebrate populations within historic levels throughout the natural range of eelgrass beds. Target: Identify and then sustain a diversity of species, and density and size structure of eelgrass-associated invertebrate assemblages that is similar to historical conditions. Measure: Species diversity and population density and size structure. Issue 1: The distribution and population status of eelgrass beds and associated fauna is unknown in most parts of the state. Conservation actions: a) Identify remote sensing technologies, including advanced satellite imagery that may allow for large-scale mapping and monitoring of eelgrass beds statewide. b) Train local community groups to monitor species. Issue 2: There is a lack of information on species diversity associated with eelgrass habitats. Conservation action: Select 2–3 representative eelgrass beds from across the state for intensive monitoring of the population status of the bed and species diversity of associated fauna assemblages. Beds would be selected based on the location of previous studies, such as Izembek Lagoon, Sitka Sound, and Kachemak Bay. Issue 3: Future increased mariculture in the state may have a negative effect on eelgrass- associated invertebrates. Appendix 4, Page 5 Conservation actions: a) Locations selected